Embodiments of the inventive concept described herein relate to a retro-reflective sheet and a method for manufacturing the same, and more particularly, to a retro-reflective body that may enhance visibility by improving light reflecting efficiency in a colored area at night, and a method for manufacturing the same.
A retro-reflective sheet is a reflective body that directly reflects incident light including a light condensing layer and a reflective layer in an incident direction. The retro-reflective sheet generally has a sheet shape, and is machined to have a desired pattern on a surface of a body of an attachment object to be attached to a road sign or a selected part of a uniform of a firefighter or the like through thermal fusion or sewing, thereby enhancing visibility such that it is easily displayed at a place, of which a surrounding environment is dark. Accordingly, if the retro-reflective sheet is attached to clothing of a person, who works on a road or at a dangerous place, such as a garbage collector, a firefighter, a policeperson, a laborer in a factory, a construction field worker, and a safety agent in the field, protection and safety of the wearer may be effectively guaranteed by allowing the surrounding people to firmly identify a location of the wearer.
Further, the retro-reflective sheet has a stripe pattern shape that alternately formed with reflective areas in which a colored area reflects light and thus may secure visibility even at night. The reflective area has a structure in which a light collecting layer is formed by attaching beads onto the reflective layer, on which metal such as aluminum is deposited, and the colored area includes a colored layer, on which an organic binder including a colored pigment having fluorescent or light accumulating characteristics is applied.
The retro-reflective sheet according to the related art is disclosed in Korean Patent No. 10-0935540 (entitled ‘Retro-reflective Sheet and Method for Manufacturing the Same’).
The retro-reflective sheet according to the related art includes: a base in which reflective areas RA and colored areas FA are alternately formed; a colored part including a first bonding layer formed by applying a bonding synthetic resin on an entire surface of the base, a colored layer formed by applying a bonding synthetic resin in which fluorescent pigments are mixed onto the first bonding layer, and a first light condensing layer formed by scattering a plurality of beads on the colored layer such that portions of the bodies of the beads are buried; and a reflective part including a second bonding layer formed by applying the bonding synthetic resin onto the reflective area RA on the first light condensing layer of the colored part, a reflective layer formed by depositing metal having light reflecting characteristics on the second bonding layer such that the metal has a thin film shape, a primer layer formed by applying a bonding synthetic resin having transparency characteristics onto the reflective layer, and a second light condensing layer formed by scattering a plurality of beads on the primer layer such that portions of the bodies of the beads are buried.
In this case, the colored layer may selectively include a fluorescent pigment and a fluorescent material including a fluorescent pigment, or a light accumulating pigment and a light accumulating material including a light accumulating pigment, or may include a fluorescent material and a light accumulating material together to emit light through a fluorescence operation at night or emitting light that has been accumulated by absorbing light during the day or in the interior of a building, at night, thereby enhancing visibility at night or in a dark place. Further, if the colored layer includes a fluorescent material and a light accumulating material together, it may perform a fluorescence operation and a light accumulating operation at the same time. In this case, the light emitted from the colored layer has colors such as red (R), green (G), and blue (B) according to the fluorescent material or the light accumulating material.
In this case, the quantity of light reflected from the reflective area is approximately 500 cd/lux*m2, and the quantity of light reflected from the colored area is not more than 30 dc/lux*m2). Accordingly, when the widths of the reflective layer and the colored layer are the same, the quantity of light reflected from the retro-reflective sheet is approximately 265 cd/lux*m2.
Accordingly, because the retro-reflective sheet according to the related art reflects a small quantity of light on the colored area except for the reflective area, it decreases visibility.